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What is HDMI 2.1a? Yet another HDMI spec may be on the way

What is HDMI 2.1a? If you thought the current HDMI situation was confusing, prepare for things to get even more convoluted with the reported launch of HDMI 2.1a.

As of right now, there are a few important specs you need to be looking at if you’re buying a new television for gaming. One of them is the presence of HDMI 2.1 ports required for 4K 120Hz variable refresh rate gaming on the PS5 and Xbox Series X.

With the next-gen consoles, a TV with at least one HDMI 2.1 port, and an Ultra High Speed certified HDMI cable, you’re on the fast track to getting the best visuals possible from the new machine. Easy, right?

Well, the HDMI Forum is reportedly planning to shake things up a little by launching another new standard at CES 2022, set to be called HDMI 2.1a.

What is HDMI 2.1a?

The HDMI Forum hasn’t officially announced anything yet and may be waiting for CES 2022 to get underway on January 5 before dropping the official word.

However, The Verge seems to have obtained some details on the planned update, saying it will add a new feature called Source-Based Tone Mapping (SBTM) to the standard. According to the report, this its HDR-centric.

The report says SBTM “offloads some of the HDR tone mapping to the content source (like your computer or set-top box) alongside the tone mapping that your TV or monitor is doing.”

The idea behind the tech isn’t to replace existing standards like HDR10+ or Dolby Vision (thank goodness, the last thing we need is another competing standard). Instead, the report says, SBTM will “better optimise the content it passes to the display” minus the need for manual calibration of the display.

What does HDMI 2.1a mean for me?

Does it mean you’re going to have to get another new TV or set-top box to stay compatible with the latest standard and receive that HDR boost offered by Source-Based Tone Mapping? Thankfully not! According to the report, HDMI 2.1a support can be added by manufacturers through a firmware update. HDMI 2.1 ports will automatically become HDMI 2.1a ports, but it’s up to manufacturers to implement the support.

HDMI 2.1a release date

As soon as HDMI 2.1 is officially announced, we’ll be back with all of the full details, including the release date and rollout plans. We have contacted the HDMI Forum for a statement.

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